I have establish a campus Wifi using 6 nos RB433ah(Dual Wireless Card) along with 6 sector antenna.
And these sector antenna polarized in three location,in each location 2 nos of sector antenna installed.And 40 nos of CPE is connected with these 6 nos sector by APbridge and client mode.Each WLAN interface is use different frequency.Every CPE is terminate in 8 port switch.in each swith is also connect 2 nos AP (TP-Link 5110G CPE also make by Tp-link)

Now problem is that all CPE to sector link is not stable for long time.All are getting down frequently.I am attaching a NMS diagram.

Please help me. I discussed with many expert but no one suggest any solution.

Please help me?????????

I have establish a campus Wifi using 6 nos RB433ah(Dual Wireless Card) along with 6 sector antenna.

Self interference could be a problem if using the same band on the same board. Also, are there wired connections between the AP's or have you setup WDS?